Invalid double escaping of nested arrays in SSR

[axel-habermaier]

Consider the following code:

function Test() {
  const a = ["<"];
  return <div>{[a, a]}</div>;
}

During SSR, this incorrectly renders the HTML <div>&amp;lt;&amp;lt;</div>, i.e., the < is escaped twice and is thus shown as << in the browser.

I expected SSR to generate the single-escaped HTML <div>&lt;&lt;</div> which then renders as << in the browser.

[axel-habermaier]

Update: The underlying reason seems to be that the array a is unexpectedly modified during rendering! So if a were at module scope, there would be additional escaping for each render.